Plastic corrugated container with improved fold lines and method and apparatus for making same

ABSTRACT

A reusable plastic container is provided. The container includes a plastic container body having opposing side panels and opposing end panels. The container body also includes top side panel flaps attached to a top portion of each side panel, and bottom side panel flaps attached to a bottom portion of each side panel. The container body has top end panel flaps attached to a top portion of each end panel, and bottom end panel flaps attached to a bottom portion of each end panel. The top and bottom side panel flaps are each defined with respect to the side panels by a fold line. The fold lines including at least one scored portion and at least one welded portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention generally relates to a reusable plastic corrugatedcontainer that is capable of being used interchangeably within andinterchangeably with expendable corrugated containers in existingautomated packaging equipment and to a method and apparatus for formingthe container.

BACKGROUND OF THE INVENTION

Reusable plastic packaging has in recent years been used to store andtransport all manner of goods and materials via air, highway, and rail.Such goods and materials run the gamut, including general merchandise,health and beauty aids, automotive parts, beverage, bakery,pharmaceuticals, and food products.

Reusable packaging typically lasts for multiple trips making it morecost effective than wood fiber corrugated or other disposable packaging,which is typically discarded after a single use. Plastic packaging isboth reusable and recyclable, and therefore, environmentally friendly.

Until the present invention, one drawback to plastic packaging is thatit cannot be used with existing automated corrugated paper packagingequipment. An example of such equipment is shown in U.S. Pat. No.7,886,503 to Chase, et al. Such equipment is designed for new corrugatedpaper boxes. New paper corrugated boxes are almost perfectly straightand flat. Existing reusable plastic packaging such as plastic corrugatedboxes, however, have top and bottom flaps that do not return to asufficiently flat position after they have been used and broken down.Thus, existing plastic corrugated boxes will not work with automatedcorrugated paper packaging equipment to allow them to be reused.

The plastic corrugated container of the present invention provides areusable plastic container that can be used interchangeably withexisting automated paper corrugated packaging equipment. Fold lines forthe top and bottom flaps include a combination of welded and scoredportions that return the flaps to a substantially planar configurationwith the container end and side panels after each use.

SUMMARY OF THE INVENTION

The present invention relates to a reusable corrugated plastic containerin the form of a rectangular box. The container is formed from a flatblank of extruded plastic. The extruded plastic includes a first outerlayer, a second outer layer and a plurality of flutes between the firstouter layer and second outer layer. The blank is converted with foldlines between the side and end walls of the container with top andbottom flaps extending from the top and bottom portions of the side andend walls. These fold lines are designed to include both scored portions(i.e., partially crushed) and welded portions (e.g., heat welded). Priorto folding, the flaps are substantially coplanar with the respectiveside or end wall.

The welded portions of the fold line allow the top and bottom flaps tobe easily folded in existing package erecting machines. The weldedportions substantially keep their form over time. The scored portionsalso allow for folding of the flap, however, these portions also allowthe memory of the plastic to recover over time to enable the flaps toagain become coplanar with the respective side or end walls after use.This facilitates the reuse of the container after a first (orsubsequent) use because the package erecting and packing machineryrequires the containers to be straight.

In one embodiment of the present invention, a reusable plastic containeris provided. The container includes a plastic container body havingopposing side panels and opposing end panels. The container body alsoincludes top side panel flaps attached to a top portion of each sidepanel, and bottom side panel flaps attached to a bottom portion of eachside panel. The container body has top end panel flaps attached to a topportion of each end panel, and bottom end panel flaps attached to abottom portion of each end panel. The top and bottom side panel flapsare each defined with respect to the side panels by a fold line. Each ofthe fold lines including at least one scored portion and at least onewelded portion. Additional score and/or weld lines can be provided asdesired or needed. Further other fold lines in the container can beformed in a similar manner, having both scored and welded portions in asingle line.

In another embodiment, the present invention provides a blank for areusable plastic container. The blank includes a first end panel havingfirst and second ends and top and bottom portions, and a first sidepanel having first and second ends and top and bottom portions. Thefirst end of the first side panel is attached to the second end of thefirst end panel. A second end panel has first and second ends and topand bottom portions. The first end of the second end panel is attachedto the second end of the first side panel. A second side panel has firstand second ends and top and bottom portions. The first end of the secondside panel is attached to the second end of the second end panel. A topflap is attached along top flap fold lines to the top portion of each ofthe first and second end panels, and first and second side panels. Abottom flap is attached along bottom flap fold lines to the bottomportion of each of the first and second end panels, and first and secondside panels. At least one of the top and bottom flap fold lines includesat least one welded portion and at least one scored portion. Again,additional scored and welded portions can be provided, and other foldlines in the blank can include a combination of scored and weldedportions.

In a further embodiment, an apparatus for making a reusable plasticcontainer from a blank is provided. The apparatus includes a bottomplaten and a top platen. At least one of the top or bottom platensincludes a rule for creating a fold line having at least one scoreforming portion for forming at least one scored portion of the foldline. The rule also has at least one weld forming portion for forming atleast one welded portion of the fold line. A heating element is providedeither against the weld forming portion of the rule, or on an opposingplaten to provide heat for the weld in the fold line.

In another embodiment, a method for making a reusable plastic containeris provided. The method includes the steps of providing a plasticcorrugated blank, and creating a fold line in the blank. The step ofcreating the fold line includes scoring a first portion of the fold lineand welding a second portion of the fold line.

In another embodiment, a fold line for a plastic corrugated container isprovided. The fold line includes at least one scored portion, and atleast one welded portion.

Additionally, the blank can be formed to have smooth outer edges. Thiscan be accomplished after or part of an extruding process by pressing agenerally C-shaped hot plate against the edges of the extruded sheet.

The blank can be provided with a connecting segment on either end of theblank having a reduced thickness. The connecting segments are used toconnect the ends together for form a functional container. Theconnecting segment must be such that the partially broken down containerwould lay flat to be used with existing packaging equipment.

Other features and advantages of the invention will be apparent from thefollowing specification taken in conjunction with the following Figures.

BRIEF DESCRIPTION OF THE FIGURES

To understand the present invention, it will now be described by way ofexample, with reference to the accompanying Figures in which:

FIG. 1 is a plan view of a plastic corrugated blank having fold lines ofan embodiment of the present invention.

FIG. 2 is an enlarged view of section 2 of FIG. 1 showing the scoredportion and welded portion of a fold line of an embodiment of thepresent invention.

FIG. 3 is a perspective view of a welded portion of a fold line of anembodiment of the present invention.

FIG. 4 is a perspective view of a scored portion of a fold line of anembodiment of the present invention.

FIG. 5 is a partially erected plastic corrugated container of anembodiment of the present invention.

FIG. 6 is a plan view of a plastic corrugated blank having fold lines ofan embodiment of the present invention.

FIG. 7A is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 7B is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 8A is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 8B is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 9A is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 9B is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 10 is a schematic view of an apparatus for making a plasticcorrugated blank in accord with an embodiment of the present invention.

FIG. 11A is a schematic view of a tab and cutout in a plastic corrugatedblank in accord with an embodiment of the present invention beforeengagement.

FIG. 11B is a schematic view of a tab and cutout in a plastic corrugatedblank in accord with an embodiment of the present invention afterengagement

FIG. 12 is a perspective of a stack of pre-erected containers for usewith a packaging erector machine.

FIG. 13 is a perspective view of a stack of partially constructed and/orbroken down containers for use with a packaging erector machine.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiments in many differentforms, there is shown in the Figures, and will herein be described indetail, preferred embodiments of the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention, and is not intended to limit the broadaspect of the invention to the embodiments illustrated.

Referring to the drawings, in an embodiment of the present inventionshown in FIG. 5, an erected and partially set up plastic corrugated boxor container 10 is provided. The container 10 includes a container body12 having a first end panel 14 and a second end panel 16, and a firstside panel 18 and a second side panel 20′. The first and second endpanels 14 and 16 each have top portions 22 and bottom portions 24. Thefirst and second side panels 18 and 20 also each have top portions 26and bottom portions 28.

Bottom end panel flaps 30 are attached to the bottom portions 22 of thefirst and second end panels 14 and 16 along fold lines 32. Top end panelflaps 34 are attached to the top portions 22 of the first and second endpanels 14 and 16 along fold lines 36. Bottom side panel flaps 38 areattached to the bottom portions 28 of the first and second side panels18 and 20 along fold lines 40. Top side panel flaps 42 are attached tothe top portions 26 of the first and second side panels 18 and 20 alongfold lines 43.

The container 10 is formed from a plastic blank 44 shown in FIGS. 1 and2. The blank 44 is an extruded sheet of plastic having a first layer 66and a second layer 68, and a plurality of flutes 70 between them. (SeeFIGS. 3 and 4). The blank 44 includes the first end panel 14 having afirst end 46 and a second end 48. The first side panel 18 has a firstend 50 and a second end 52. The first end 50 of the first side panel 18is attached to the second end 48 of the first end panel 14. The secondend panel 16 has a first end 54 and a second end 56. The first end 54 ofthe second end panel 16 is attached to the second end 52 of the firstside panel 18. The second side panel 20 includes a first end 58 and asecond end 60.

The first end 58 of the second side panel 20 is attached to the secondend 56 of the second end panel 16. In this pre-erected position, thebottom and top side and end panel flaps 30, 34, 38 and 42 aresubstantially planar with respect to their respective side and endpanels 14, 16, 18 and 20. The bottom and top side and end panel flaps30, 34, 38 and 42 are folded into an erected position to create thecontainer 10. FIG. 5 shows a partially erected container 10 with thebottom side and end panel flaps 30 and 38 folded and the top side andend panel flaps 34 and 42 not yet folded. In a fully erected position,the top side and end panel flaps 34 and 42 are folded to enclose thecontainer 10. After the container 10 is used, it is knocked down to apre-erected (totally flat) or a partially broken down (one end of theblank still attached to the other end) position for transport andstorage.

In one embodiment, a tab 62 is attached to the second end 56 of thesecond side panel 16. The tab 62 engages with a cutout 64 in the firstend 46 of the first end panel 14. The tab 62 and cutout 64 are sized andshaped such that when engaged, as shown in FIGS. 11A and 11B, the tab 62and cutout 64 form a connection between the first end panel 14 andsecond side panel 20 such that the panels are substantially coplanar asshown in FIG. 11B, and do not add thickness to the wall sections at thispoint. This becomes important when a large number of partiallyconstructed or broken down containers are stacked (or positioned side byside) for a container erecting machine (See FIG. 12). Even a slightincrease in thickness (above the double wall thickness of the remainderof the collapsed container) would result in a bulge in this area thatcould cause problems with the machinery.

In another embodiment, the tab or manufacturers joint flap 62 can beextruded to a thickness of approximately ⅓ the thickness of the secondside panel 20. Where the tab or manufacturers joint flap 62 and sidepanel 20 overlap can be fastened, such as by gluing, and welded to athickness equal to or less than the thickness of the side panel 20 toremove the memory from the plastic, and provide a container 10 withcoplanar end and side panels. This does not add thickness allowing thecontainer 10 to work with existing paper corrugated packaging machinery.This embodiment does not require a cutout 64. The tab or manufacturersjoint flap 62 may extend the length of the second end 60 of the secondend panel 20.

The blank 44 is preferably a corrugated plastic sheet. The blank 44includes a first layer 66 and a second layer 68. Between the first layer66 and second layer 68 are flutes 70. The blank 44 is formed as asingle, integral sheet, preferably by an extrusion process. Plasticcorrugated containers can be made to suit particular size, stiffness,resilience, and strength requirements by varying a variety ofcharacteristics or parameters, such as the thickness of the first andsecond layers 66 and 68, the overall thickness of the blank 44, thenumber of flutes 70, the plastic resin used, or other characteristics ofthe blank 44 material. Typical ranges for such parameters include 67-100flutes per foot, blank thickness of 2 to 10 mm, and plastic materialdensity of 400 to 1,000 grams per square meter. Typical materials forthe blank 44 can include plastic materials such as high densitypolypropylene and high density polyethylene.

Scored fold lines are known in the art and have been used extensivelywith paperboard containers such as cardboard. Scored fold lines aretypically formed by crushing or partially crushing one or both sides ofthe blank along the desired fold line. This weakens the blank materialso that it can be folded along such line. In addition, the crushed scoreline can include perforations at intervals along its length.

It has been found that given time, the score lines formed in plasticcorrugated packaging in this manner have a memory, meaning the materialhas a tendency to return to its original pre-erected substantiallyplanar position. Over time, typically on the order of days, the memoryof the material essentially makes the score lines disappear, makingfolding the blank along these score lines a second time difficult if notimpossible. The material is too stiff to be used in existing automatedpackaging equipment.

It has also been found that welding the first and second layers 66 and68 of the blank 44 together allows for easy folding, but substantiallynegates the memory of the material. Welded score lines have not beenpreviously used in connection with plastic corrugated packaging. Weldingonly (without providing a scored portion) may hinder the material frombeing used on existing corrugated paper packaging equipment as the topand bottom side and end panel flaps will not return to their pre-erectedsubstantially planar configuration with the side and end panels (SeeFIG. 13).

To overcome this problem, a combination of welding and scoring the foldlines of the present invention is used. This provides the desiredcombination of ease of foldability and memory to permit the top andbottom side and end panel flaps to be folded and return to substantiallytheir pre-erected planar configuration with the side and end panelsafter use and knock down. Thus, plastic packaging made in accord withthe present invention can be reused and can be erected again usingexisting packaging equipment.

To this end, the fold lines 32, 26, 40 and 43 include at least onewelded portion 72 (FIG. 3) and at least one scored portion 74 (FIG. 4).Additional welded portions 72 and/or scored portions 74 can be used foreach fold line. In an embodiment shown in FIGS. 1, 2, 5 and 6, scoredportions 74 are located at the first and second ends 50, 52, 58 and 60of the side panels 18 and 20, and the first and second ends 46, 48, 54and 56 of the end panels 14 and 16.

The scored portions 74 can be sized and spaced along the fold lines 32,36, 40 and 43 to achieve desired foldability and memory characteristicssuch that the bottom and top end and side panel flaps 30, 34, 38 and 42return to their substantially pre-erected position to allow it to beused with existing packaging equipment. The scored portions 74 can becrushed and may include perforations. The remainder of the fold lines32, 36, 40 and 43 between the scored portions 74 include welded portions72.

As an example, in a plastic corrugated container 10 having dimensions 12inches wide by 20 inches long by 8 inches high, and made of a materialhigh density polypropylene, having a blank 44 thickness of 3-4 mm, andninety flutes 70 per foot, it has been found that scored portions ofapproximately 1½ inches in length at the first and second ends 46, 48,50, 52, 54, 56, 58 and 60 of the side and end panels 14, 16, 18 and 20provides the desired characteristics. For longer side panels 18 and 20as shown in FIG. 6, additional scored portions 74 can be located alongthe length of the fold lines 32, 36, 40 and 43. Alternatively, thescored portions 74 can be of longer or shorter length to achieve thesame desired result. The same is true of the shorter end panels 14 and16 of FIG. 6, wherein only one scored portion 74 may be desired ornecessary.

The welded portion 72 and scored portion 74 are formed using anapparatus 76, which includes a bottom platen 78 and a top platen 80. Inone embodiment shown in FIGS. 7A and 7B, the top platen 80 includes arule 82. FIG. 7A shows the apparatus before fold lines 32, 36, 40 and 43are formed in the blank 44. FIG. 7B shows the blank 44 are the foldlines are formed. The rule 82 includes a weld-forming portion 84 andscore-forming portion 86. The score forming portion 86 is recessed withrespect to the weld-forming portion 84.

For the welded portions 72 of the fold lines 32, 35, 40 and 43, the rule82 is heated by a heating element or heater 88. The heater 88 heats therule 82 to a temperature sufficient to form a welded portion 72 alongthe fold lines 32, 36, 40 and 43. This temperature will depend at leastin part on the material used. Alternately, the bottom platen 78 can beheated at portions aligning with the weld-forming portions 84 of therule 82 to the same effect. The rule 82 can include serrations in thescore-forming portion 86.

In operation, the bottom platen 78 remains stationary while the topplaten 80 is moved in a vertical direction. The blank 44 is placedbetween the bottom platen 78 and top platen 80. The top platen 80including the rule 82 is lowered. The rule 82 contacts the blank 44. Theweld-forming portion 84 welds the first layer 66 of the blank 44 to thesecond layer 68. The score-forming portion 86, since it is recessed fromthe weld-forming portion 84, forms the scored portion 74 of the foldlines 32, 36, 40 and 43.

FIGS. 8A and 8B are similar to FIGS. 7A and 7B, but show an embodimentwhere scored portions 74 and welded portions 72 are formed alternatelyat selected desired intervals along the fold lines 32, 36, 40 and 43 asshown in the blank 44 of FIG. 6. This embodiment may be desirable where,for instance, the length of the side panels 18 and 20 and end panels 14and 16 of the container 10 and blank 44 is such that the return strengthof these panels is sufficient to return flaps 30, 24, 38 and 42 tosubstantially their pre-erected position.

FIG. 9A shows an embodiment where the bottom platen 78 rather than thetop platen 80 is heated as shown in FIGS. 7A, 7B, 8A, and 8B. FIG. 9Bshows an embodiment where both the top and bottom platens 78 and 80 areheated, including the rule 82.

FIG. 10 shows an apparatus 96 for sealing an end 98 of the bottom andtop side and end flaps 30, 34, 38 and 42. Sealing is desirable incertain applications such as transport and storage of food items.Sealing prevents food materials from lodging in the interstices of theflutes 70, and bacteria from growing therein. The apparatus 96 includesa heated sealing bar 100 with a generally C-shaped section 102. Theheated sealing bar 100 contacts the end 98 of a flap 30, 34, 38 or 42and partially melts the end 98 to seal it and create a smooth arcuatesurface. In the past, heat scoring was used to seal the edges. However,this produces a sharp edge that can be hazardous to those handling thecontainers.

While the specific embodiments have been illustrated and described,numerous modifications come to mind without significantly departing fromthe spirit of the invention and the scope of protection is only limitedby the scope of the accompanying Claims.

I claim:
 1. A reusable plastic container, the container comprising: aplastic container body having opposing side panels and opposing endpanels; the container body having top side panel flaps attached to a topportion of each side panel, and bottom side panel flaps attached to abottom portion of each side panel; the container body having top endpanel flaps attached to a top portion of each end panel, and bottom endpanel flaps attached to a bottom portion of each end panel; and the topand bottom side panel flaps each defined with respect to the side panelsby a fold line, each of the fold lines including at least a first scoredportion and a separate at least a first welded portion, wherein thescored and welded portions alternate along a continuous section of thefold line.
 2. The reusable plastic container of claim 1 furthercomprising the top and bottom end panel flaps each defined with respectto the end panels by a fold line, each of the fold lines including afirst scored portion and a separate first welded portion.
 3. Thereusable plastic container of claim 1 wherein the plastic container bodyand the top and bottom side and end panel flaps are formed from aplastic corrugated blank.
 4. The reusable plastic container of claim 1wherein at least one fold line includes more than one scored portion. 5.The reusable plastic container of claim 1 wherein at least one fold lineincludes more than one welded portion.
 6. The reusable plastic containerof claim 1 wherein at least one fold line includes a scored portionlocated at each of the first and second ends of the side panels.
 7. Thereusable plastic container of claim 2 wherein at least one fold lineincludes a scored portion located at each of the first and second endsof the end panels.
 8. The reusable plastic container of claim 1 whereinthe plastic container body and the top and bottom side and end panelflaps are formed from a plastic corrugated blank, and the first scoredportion is formed by crushing the blank.
 9. The reusable plasticcontainer of claim 1 wherein the first scored portion includesserrations.
 10. The reusable plastic container of claim 1 wherein theplastic container body and the top and bottom side and end panel flapsare formed from a plastic corrugated blank, the blank having first andsecond layers, and the separate first welded portion is formed bywelding such that the first and second layers are welded together.
 11. Areusable plastic container comprising: a plastic container body having afirst side wall, a second side wall, a first end wall and a second endwall; a first panel connected to the first side wall by a first foldline, the first fold line having at least a first scored portion and aseparate at least a first welded portion; wherein the scored and weldedportions alternate along a continuous section of the fold line.
 12. Thecontainer of claim 11 further comprising a second scored portion in thefirst fold line.
 13. The container of claim 11 further comprising aseparate second welded portion in the first fold line.
 14. The containerof claim 11 wherein the container body further comprises a first bottomflap connected to the first side wall by a second fold line, the secondfold line having a first scored portion and a separate first weldedportion.
 15. The container of claim 11 wherein the container body isformed from a single sheet of corrugated plastic.
 16. The container ofclaim 11 wherein a first edge of the sheet includes a smooth roundededge.
 17. The container of claim 11 wherein each of the second sidewall, first end wall and second end wall include a top flap connected bya fold line and a bottom flap connected by a fold line.
 18. Thecontainer of claim 17 wherein each of the fold lines connecting the topflaps and bottom flaps to the second side wall, first end wall, andsecond end wall have a first scored portion and a separate first weldedportion.
 19. The container of claim 18 wherein each of the fold linesconnecting the top flaps and bottom flaps to the second side wall, firstend wall, and second end wall have a second scored portion and aseparate second welded portion.